1. Field of the Invention
The present invention relates to a tape reproducing apparatus and, more particularly, to a tape reproducing apparatus capable of being incorporated in a compact cassette-type tape player.
2. Description of the Prior Art
Generally, there are two types of drive systems for tape players. One of them uses the drive motor shaft as the capstan of the tape player. In theory, such a "direct drive" system is simple. However, the capstan must be rotated at a low speed, with a minimum of vibration, at a very uniform rate and without induction noise from the motor. In practice those requirements make known direct drive systems expensive and thus unsuitable for massmarketed tape players.
The other type of drive system uses a belt to transmit the rotation of the motor to a flywheel, the shaft of which comprises the capstan. The advantage of a "belt drive" system lies in its use of a flywheel for masking vibration and irregular rotation of the motor. In addition, the motor does not have to be near the capstan as it does in a direct drive system. As a result, belt drive systems are preferred in mass-marketed tape players, both cassette and open-reel as well as in many professional-class open-reel tape players.
Manufacturers are constantly attempting to reduce the size of portable cassette-type tape players. A particularly difficult problem to overcome has proved to be reducing the thickness of such a tape player. One proposal for reducing the thickness of a cassette-type tape player involves the use of a reduced-diameter cylindrical drive motor and orienting it so that the shaft lies parallel to the cassette. Thus, the motor shaft is perpendicular to the capstan and the drive belt must be twisted from one plane into another. In addition, the reduction of the diameter of the motor reduces the power capacity of the motor which places a limit on how small the motor can be made.
Another proposal for making a thin cassette-type tape player involves the use of a flat motor. The rotor and stator of a flat motor are substantially planar and parallel to each other, with the motor shaft normal to the motor plane. Using a flat, thin motor would, of course, enable the tape player to be made thinner. However, practically speaking, the motor shaft must be mounted in bearings. To reduce vibration and increase performance, there should be two bearings located as far apart from each other as possible. Therefore, the tape player must be thick enough to enable the bearings to be spaced apart a sufficient distance to provide the necessary rotational stability to the motor shaft. The only alternative to widely spacing the bearings is the use of additional restrictions on the rotating shaft along its length. However, such restrictions introduce frictional losses and thus require a more powerful motor, which is a disadvantage in a portable tape player.